Alerts Internet Security systems Security Alert January 25, 2003 Microsoft SQL Slammer Worm Propagation Synopsis: ISS X-Force has learned of a worm that is spreading via Microsoft SQL servers. The worm is responsible for large amounts of Internet traffic as well as millions of UDP/IP probes at the time of this alert's publication. This worm attempts to exploit MS/SQL servers vulnerable to the SQL Server Resolution service buffer overflow (CVE CAN-2002-0649). Once a vulnerable computer is compromised, the worm will infect that target, randomly select a new target, and resend the exploit and propagation code to that host. Impact: Although the Slammer worm is not destructive to the infected host, it does generate a damaging level of network traffic when it scans for additional targets. A large amount of network traffic is created by the worm, which scans random IP addresses for vulnerable servers. Billions of attacks have been detected in the last 12 hours from various industry sources, including ISS MSS (Managed Security Services). ISS has received reports that several major national ISPs were either experiencing severe latency or were completely unreachable during the same time frame. Affect Versions: Microsoft SQL Server 2000 Microsoft Desktop Engine (MSDE) 2000 Note: Unpatched or base installations older than SP3 are vulnerable. Description: The Slammer worm propagates via Microsoft SQL installations without patches from Microsoft Security Bulletin MS02-039 or higher. The main function of the Slammer worm is to continue propagation. No DDOS or backdoor functionality is incorporated into the worm. Infection can be removed with a reboot, however without protection in place, it is likely that vulnerable servers will be quickly re-infected. The Slammer worm loads Kernel32.dll and WS2_32.dll and then calls GetTickCount which is used as a seed for a random IP address routine. This routine then continuously sends 376 bytes of exploit and propagation code across port 1434/UDP until the SQL Server process is shut down. The Slammer worm does not prefer to scan local subnet addresses like the Nimda worm. This will limit the speed of propagation across local networks, but this scanning method generates large amounts of traffic that can overwhelm networks. The Slammer worm simply seeks to replicate itself and does not try to further compromise servers or retain access to compromised hosts. The Slammer worm does not infect or modify files, it only exists in memory. Recommendations: ISS X-Force recommends that system administrators immediately take steps to protect their networks. To remove the infection, apply the necessary patches listed below and restart the server. This action will remove the worm from memory. The following ISS updates address the issues described in this alert. These updates are available from the ISS Download center (http://www.iss.net/download) RealSecure Network Sensor XPU 20.4 and XPU 5.3 (available 9/17/02) or greater. Internet Scanner XPU 6.15 (available 7/25/02). Additionally ISS X-Force recommends blocking UDP port 1433 and 1434 traffic to protect SQL Server databases with a firewall or packet filter. Microsoft SQL Server customers should refer to the following address for information and securing Microsoft SQL Server against this buffer overflow: http://www.microsoft.com/technet/security/bulletin/MS02-039.asp. Additional Information: The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2002-0649 to this issue. This is a candidate for inclusion in the CVE list http://cve.mitre.org), which standardizes names for security problems. NGSSoftware Insight Security Research Advisory #NISR25072002, "Unauthenticated Remote Compromise in MS SQL Server 2000" at: http://www.ngssoftware.com/advisories/mssql-udp.txt Microsoft Security Bulletin MS02-039, "Buffer Overruns in SQL Server 2000 Resolution Service Could Enable Code Execution (Q323875)" at http://www.microsoft.com/technet/security/bulletin/MS02-039.asp CERT Advisory CA-2002-22, "Multiple Vulnerabilities in Microsoft SQL Server" at: http://www.cert.org/advisories/CA-2002-22.html CERT Vulnerability Note VU#484891, "Microsoft SQL Server 2000 contains stack buffer overflow in SQL Server Resolution Service" at: http://www.kb.cert.org/vuls/id/484891 NGSSoftware Insight Security Research Advisory #NISR03092002B, "Windows .NET Server (RC1) and MSDE" at: http://www.nextgenss.com/advisories/dotnet-msde.txt Standards associated with this entry: BID-5311: Microsoft SQL Server 2000 Resolution Service Stack Overflow Vulnerability ______ About Internet Security Systems (ISS) Founded in 1994, Internet Security Systems (ISS) (Nasdaq: ISSX) is a pioneer and world leader in software and services that protect critical online resources from an ever-changing spectrum of threats and misuse. 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